1. Field of the Invention
The present disclosure relates to a compressor, and more particularly, to a rotary compressor divided into a suction chamber and a compression chamber by a vane being brought into contact with a rotating roller.
2. Description of the Related Art
In general, compressors may be divided into a rotating type and a reciprocating type according to a method of compressing refrigerant. The rotating type compressor varies a volume of a compression chamber while a piston performs a rotational or orbiting movement in a cylinder, and the reciprocating type compressor varies a volume of a compression space while a piston performs a reciprocal movement in a cylinder. A rotary compressor which compresses refrigerant while a piston rotates using a rotational force of a driving motor is well known as the rotary compressor.
The rotary compressor has continuously emphasized the development of technologies associated with high efficiency, miniaturization, and the like. Furthermore, the development of technologies for increasing a variation range of a compressor operating speed to satisfy more cooling capacity has been carried out.
The foregoing rotary compressors may be divided into a single rotary compressor and a dual rotary compressor. The dual rotary compressor may be also divided into a scheme in which a plurality of cylinders are stacked to form a plurality of compression spaces and a scheme in which a plurality of compression spaces are formed in one cylinder.
The former case is a scheme in which a plurality of rollers are provided on a rotational shaft with height differences, and the plurality of rollers alternately suck, compress and discharge refrigerant in each compression space while performing an eccentrically rotational movement in a compression space of each cylinder. Accordingly, the former case has a disadvantage in which a plurality of cylinders may be provided in an axial direction, thereby increasing a size of the compressor to that extent as well as increasing the material cost.
On the contrary, the latter case is a scheme in which one oval shaped roller 2 is provided on the rotating shaft 1, and the one roller 2 forms a plurality of compression spaces (V1)(V2) in one cylinder 4 along with two vanes (3A)(3B) to suck, compress and discharge refrigerant at the same time in both the compression spaces (V1)(V2) while performing an eccentrically rotational movement. Accordingly, the latter case has an advantage in which refrigerant is sucked, compressed and discharged at the same phase in the two compression spaces (V1)(V2) to decrease a mechanism sliding area, allow miniaturization and cancel a gas force toward an axial center, thereby allowing acceleration due to a decrease of journal portion reaction force.
However, the foregoing rotary compressor in the related art may have a problem of an overpressure loss due to a short compression period and a machine loss increase due to no roller rotation. In other words, as the vanes (3A)(3B) performing a linear movement is brought into contact with an outer circumferential surface of the roller 2 performing a rotational movement without rotation, a mechanical friction loss increases between the roller 2 and the vanes (3A)(3B). According to the mechanical friction loss generated between the roller 2 and the vanes (3A)(3B), a linear velocity proportionally may increase as increasing a number of vanes in the same inner diameter and height condition of the cylinder, thereby significantly reducing the compressor efficiency.
Furthermore, according to the rotary compressor in the related art, an front end of the vanes (3A)(3B) may be brought into contact with an outer circumferential surface of the roller 2 rotating without rotation to increase a mechanical friction loss between the roller 2 and the vanes (3A)(3B), but if a back pressure to each of the vanes (3A)(3B) is too reduced in consideration of this, it may cause a problem in which refrigerant is leaked into the suction chamber while decreasing a contact force between the vanes (3A)(3B) and the roller 2. Such a problem may increase refrigerant leakage since in case where the roller 2 is formed in an oval shape, a contact force between the vanes (3A)(3B) and the roller 2 decreases to the least value at a position where a rotating angle of the roller is 90° at a time point in which the vanes (3A)(3B) make contact with a minor axis of the roller 2.
Furthermore, the rotary compressor in the related art has a problem in which a release point at which the roller 2 is separated from the vanes (3A)(3B) may occur according to a rotation angle of the roller 2, and in particular, in case where the roller 2 is in an oval shape, a variation amount of a contact point between the vanes (3A)(3B) and the roller 2 increases, and due to this, an area of generating a release point between the vanes (3A)(3B) and the roller 2 also increases to limit the design freedom of the compressor.
Furthermore, according to the rotary compressor in the related art, as an end portion of the vanes (3A)(3B) facing the roller 2 is formed such that the center (O) of a curvature radius (R) is located at a length directional center line (CL) of the vanes (3A)(3B) as illustrated in FIG. 2A, an end area of the vane (3A) receiving a gas force (Fs) from a side of the suction chamber will be the same as that of the vane (3A) receiving a gas force (Fc) from the compression chamber, particularly on the basis of a contact point (P) at a rotation angle of 90°. It also has a problem in which a gas force that can be received by an end portion of the vane (3A) is limited to increase a mechanical friction loss generated between the vane and the roller.
Furthermore, according to the rotary compressor in the related art, the roller 2 is protruded from vane slots (4A)(4B) to partition between suction chambers (V11)(V21) and compression chambers (V12)(V22), and thus the vanes (3A)(3B) receives a side directional gas force (Fside) according to a pressure difference between the suction chamber and the compression chamber. As a result, the foregoing side directional gas force (Fside) is further applied to the second side surface (3b) protruded to the compression space (V1) while at the same time reaction forces (R1)(R2) in opposite directions to each other are generated on a first side surface (3a) facing an inner circumferential open end and a second side surface (3b) facing an outer circumferential open end of the vane slot (4A) on both side surfaces of the vane (3A) facing the vane slot (4A) as illustrated in FIG. 2B. Accordingly, the reaction forces (R1)(R2) applied to both side surfaces of the vane significantly may increase, thereby causing a problem of increasing a mechanical friction loss between the vane and the cylinder while the vane (3A) and the vane slot (4A) are excessively adhered to each other.
Furthermore, according to the rotary compressor in the related art, as the vanes (3A)(3B) receive a larger side directional gas force (Fside) in a suction chamber direction due to a pressure of the compression chamber in which the vanes (3A)(3B) have a relatively high pressure, a gap between the roller and the vane may be generated, thereby causing a problem in which refrigerant is leaked while a contact force between the roller and the vane excessively decreases. It may increase an area of the vane exposed to the compression chamber while increasing a maximum protrusion amount of the vanes (3A)(3B) in case of an oval shaped roller 2, and due to this, a side directional gas force (Fside) receiving at the compression chamber by the vane may further increase, thereby causing a problem of increasing refrigerant leakage.